Rational Numbers:Rational numbers are numbers that can be expressed as a ratio of two integers, such as fractions, whole numbers, and terminating or repeating decimals.
Irrational Numbers:Irrational numbers are numbers that cannot be expressed as a ratio of two integers, such as $\pi$, $\sqrt{2}$, and $e$. They have non-repeating, non-terminating decimal representations.
Number Line:The number line is a visual representation of the real number system, where each point on the line corresponds to a unique real number.